Raid 5 how it works?

B

by_EL2019-06-27 16:05:04

RAID

by_EL, 2019-06-27 16:05:04

RAID 5 3 disks what will be the speed? That is, if in detail, RAID 5 s. 3 - how many disks will be combined disks? like raid 0? how will it actually work

Reply

Answer the question

In order to leave comments, you need to log in

6 answer(s)

D

Drno, 2019-06-27
@by_EL

In raid 5, raid 0 is not used.
But if "very conditionally" - then there will be 1.5 disks out of 3.
And I would not advise this raid at all. Or raid 1 or raid 10

R

Ronald McDonald, 2019-06-27
@Zoominger

First one question:
Then another:
Then the third incomprehensible:
And then schizophasia.

Z

Zettabyte, 2019-06-28
@Zettabyte

what will be the speed?

What speed do you mean: reads or writes?
Readings -- will be higher, tk. flows from different disks are independent. Recording, especially random, will be slower than RAID0, I think by 10-20 percent. An exception will be the situation when the stripe is recorded in its entirety.
RAID5 and RAID0 have different tasks. The first provides greater reliability (actually - up to a certain number of disks), the second - greater speed at the cost of reducing reliability in proportion to the number of disks.
By the way, RAID 5 with a failed one disk turns, in fact, into RAID 0.

-

-=TuXaPb=-, 2020-01-10
@Storozh2005

Wouldn't it be easier to give citizen by_EL links to a more or less detailed description of the levels of raid arrays, let him enlighten: https://ru.wikipedia.org/wiki/RAID ; https://en.wikipedia.org/wiki/Standard_RAID_levels .
And by the semantic formulation of questions, I got the impression that citizen by_EL is essentially a youngster who is 10-12 years old :).

R

rPman, 2019-06-27
@rPman

The speed of work will be - the minimum speed of one disk, since the recording simultaneously goes to all three disks.
There is also a minimum load on the processor (if the raid is soft), and it noticeably increases (for reading) if the array is in a state of failure (one of the disks is disabled).
Rebuilding the array is equal in write speed to the slowest disk in the array and will also take a load on the CPU, but if you do not have a calculator, then you will not notice this.
And if you work with the array at the same time as reassembling, this will reduce the speed by an order of magnitude.